Field of the Invention
The invention relates to a drilling tool for bores in solid material and, more particularly, to a drilling tool with a drill shaft and cutting devices at the end of the drilling tool.
Drilling tools are known which have a drill shaft with which the drilling tool can be clamped in a suitable seating, and adjoining which in the axial direction is a working region of the tool. In the region of an end face of the tool, the following varieties of cutting devices are fastened, either releasably, e.g. screwed or clamped, or unreleasably, e.g., adhered or soldered in suitable seatings:
a cutter which is substantially symmetrical with respect to the drill axis, PA1 at least one cutter which is arranged so that the cutting edge extends from the periphery of the diameter to be produced to at least the center of the diameter to be produced or up to a cross cutter. PA1 two or more cutters, which can have different geometries, and which are arranged such that each cutting edge covers a given region of the diameter to be produced. PA1 one of the previously stated arrangements, in which the cutting device is embodied as an interchangeable cutter head, in which all of the cutter geometry is machined from one cutting material blank. PA1 one of the previously stated arrangements, in which the cutting device is embodied as an interchangeable cutter head, in which only the immediate cutting region consists of the desired cutting material, e.g., brazed-in cutters.
When the drilling tool has at least two cutters, then the cutters are distributed radially at the periphery of the tool, and the angular peripheral distances must not be equally large. If the drilling tool has at least three cutters, then a respective two or more cutters can be located in the same radial position, but at different diameter positions.
Adjoined to the cutter receiving region in all the stated variants is an axially directed tool shank having at least one recess which serves to transport out of the bore the chips which arise during machining.
These described drilling devices are produced from a cemented carbide made by powder metallurgy. In chip-producing manufacture, however, materials are understood by "cemented carbide" whose hard phase substantially consists of tungsten carbide (WC), but also of other carbide formers. The cemented carbide consisting substantially of tungsten carbide can be uncoated or can be additionally coated with a hard material.
The productivity of drilling processes is substantially determined by the features of cutting speed and forward feed, wear behavior and machining quality, and these furthermore depend directly on the properties of the cutting materials used.